# Propositional Logic

## Abstract

This chapter focuses on *Propositional Logic*, the most elementary part of mathematical logic. The standard truth-functional connectives *and*, *or*, *not*, *if-then*, and *if and only if* are systematically introduced; a natural deduction system of inference rules for these connectives is given; and mathematical proof strategies associated with these rules are explored. This material is extended in Chapter 2 to *First-Order Logic*. Together these chapters provide a sound basis for learning how to read and write deductive arguments in mathematics and elsewhere. It thus undergirds later discussions of discrete mathematical topics, where such arguments are central. Chapter 1 also provides a content basis for Chapter 7, which looks at how Boolean logic is realized using logic gates.